The rolling motion guide device of this type has a structure comprising a track rail formed with rolling member rolling grooves, a movable block provided to the track rail so as to be movable along the track rail, the movable block having a rolling member rolling groove which is opposed to the rolling member rolling groove formed to the track rail, and a row of rolling members (hereinafter referred to simply as "rolling members") disposed between the opposing rolling member rolling grooves formed to the track rail and the movable block.
The applicant of this invention had already proposed a rolling motion guide device in which a movable block is provided with a circulation passage for circulating the row of rolling members and at least part of the circulation passage is constituted as a molded portion (see Japanese Patent Laid-open Publication No. HEI 7-317762).
The molding operation is performed in such a manner that a movable block body is disposed in a molding die, then an integrally-molding is conducted by injecting molding material into a cavity formed between an inner surface of the molding die and the movable block body when the molding die is closed. In this case, conventionally, a supporting portion which engages with the rolling member rolling groove is provided in the molding die, so that the movable block body is positioned with reference to the rolling member rolling groove.
However, in the conventional method of molding the movable block described above, since the rolling member rolling groove is engaged with the supporting portion provided in the molding die, there may be a fear of the rolling member rolling groove being damaged or injured. In order to prevent such damage or injury of the rolling member rolling groove, it may be effective to reduce an engaging force between the supporting portion and the rolling member rolling groove. In this case, however, there may be a fear that the molding material will disadvantageously invade into the rolling member rolling groove and burrs are liable to occur thereto. Further, the positioning of the movable block body will be unstable.
The present invention has been achieved for solving the aforementioned problems encountered in the prior art, and an object of the present invention is to provide a method of molding a movable block for a rolling motion guide device which is capable of effectively preventing the formation of burrs in the rolling member rolling groove and accurately positioning the movable block body.